Solar Winds Blow At 200 Miles A Second

February 02, 1986|By New York Times News Service.

Q--What is solar wind?

A--Solar wind is a supersonic flow of gas, composed of ionized hydrogen and helium, that continuously blows from the sun out through the solar system. The wind results from the expansion of gases in the outermost atmosphere of the sun, called the corona.

Temperatures inside the corona, which are as high as 3 milion degrees Fahrenheit, cause gas atoms to expand and then to collide. These collisions cause the gas atoms to lose their electrons and become electrically charged particles. It is these particles that make up the solar wind.

Velocities of solar wind range from 200 to 600 miles per second. The speed, density and ion temperature of a solar wind are measured with instruments carried on spacecraft. The solar wind is responsible for the fact that gaseous comet tails point away from the sun.

Q--What exactly is the barometer?

A--Weather forecasters use the barometer to measure air pressure, the force per unit area that air exerts on any surface in contact with it. Air pressure varies according to weather conditions. A falling barometer usually indicates an approaching storm while a rising one predicts milder weather.

By drawing lines connecting places of equal atmospheric pressure on maps, forecasters determine the course of winds and storms. These lines are called isobars, from the Greek words ``iso`` and ``baros`` meaning equal and weight.